Initiating AD COP-1 service with unlock causes exception in TcSleLink

[merose]

When using INITIATE AD "With unlock" in Yamcs, a BC frame is sent over the telecommand data link. This command frame has no associated commands. This causes a NullPointerException in TcSleLink.java on line 318, the for (PreparedCommand pc : tf.getCommands()) line in the code below. I believe that should be protected by an if (tf.getCommands() != null).

    private void onCltuRadiated(CltuOk cltuOk) {
        int cltuId = cltuOk.getCltuIdentification().value.intValue();
        CcsdsTime time = CcsdsTime.fromSle(cltuOk.getRadiationStopTime());
        long yamcsTime = TimeEncoding.fromUnixMillisec(time.toJavaMillisec());
        TcTransferFrame tf = pendingFrames.remove(cltuId);
        if (tf == null) {
            log.warn("Received cltu-radiated event for unknown cltuId {}", cltuId);
            return;
        }

        if (tf.isBypass()) {
            ackBypassFrame(tf);
        }

        for (PreparedCommand pc : tf.getCommands()) {
            commandHistoryPublisher.publishAck(pc.getCommandId(), CMDHISTORY_SLE_RADIATED_KEY, yamcsTime, AckStatus.OK,
                    time.toStringPico());
        }

        uplinkReadySemaphore.release();
    }